Method of and apparatus for treating materials



Dec. 7, 1937. w. CASEY 2,101,042

METHOD OF AND APPARATUS FOR TREATING MATERIALS Filed Jan. 25, 1 935 2 Sheets-Sheet l Y O I O 0 m O m be fin I ATTORNEYJ Dec. 7, 1937. P w, SE 2,101,042

METHOD AND APPARATUS FOR TREATING MATERIALS Filed Jan. 25, 1935 2 Sheets-Sheet 2 7 V I A I 1 (a: I Q4 67 1 INVENTOR I CUZZ/iazn Cddey =BY A TTORNEIZ Patented Dec.7, 1937 METHOD OF AND APPARATUS FOR TREAT- ING MATERIALS William Casey, Kingston, Ontario, Canada, assignor to Canadian Locomotive Company, Limited, Kingston, Ontario, Canada, a. corporation of Canada Application January 23, 1935, Serial No. 2,978

' 7 Claims. (01. zio-ia'i) This invention relates as indicated to material treating apparatus and more particularly to the general type of apparatus such as is disclosed in the copending application of William R. Thomson, Serial No. 2,977, and filedJanuary 23, 1935 and which is particularly, applicable for use in separating the solid and liquidcomponents of material, such as sludges, slurrys, etc.

More particularly this invention relates to a method of and apparatus for treating materials of the character described, characterized by simplicity of construction and low cost of operation of the apparatus as well as improved results achieved by practicing the method comprising this invention.

It is a principal object of myinvention to provide an apparatus of the character described in which novel means are provided for supporting the material to be treated during the carrying on of the process which means make possible variations in saidprocess not possible by any means provided in the prior art.

It is a further object of my invention to provide an apparatus of the character described'in which improved results may be obtained by an expenditure of minimum power.

-It is a further object of my invention to pro= vide a method of the character described which results in the building up, on the filter medium in the apparatus,- of a filter cake of such character that. further dehydration thereof may be accomplished most efficiently.

It is a further object of my invention to provide a method of the characterdescribed in which additional materials are added to the filter cake during the. process of dehydration in order to vary or improve for certain purposes the characteristics of such cake as-it is discharged from,

the apparatus.

Other objects of my invention will appear as the description proceedsf To the accomplishment of the foregoing and related ends this invention therefore comprises the hereinafter described means and mode of operation, such disclosed means and mode being,

, however, only illustrative of my invention as descale of a portion of the apparatus but disclosing a modified form of -supplemental feed.

Figures 3 and 4 are likewise respectively plan and side elevational yiews drawn to an enlarged illustrated in Figure 1.

Figure 5 is aplan view of one form of suction belt or mat which may be utilized in apparatus such as is disclosed in Figure 1.

Figure 6 is a transverse sectional view of the belt or mat shown in Figure 5 taken on a plane Figure 9 is a transverse sectional view of the mat or belt illustrated in Figure 8 taken on a plane substantially indicated by the line 9-9.

Figure 10 is a sectional view of the mat illus- I trated in Figure 8 taken on a plane substantially indicated by the line Ill-i0.

Figure 11 is a plan view of yet another form of mat or belt capable of use in apparatus of the character disclosed in Figure 1.

Figure 12 is a fragmentary sectional view of the mat or belt shown in Figure 11 and taken on a plane substantially indicated by the line l2-l2.

Figure 13 is a fragmentary sectional view of a portion of an apparatus similar to that disclosed in Figure l'showing in conjunction therewith another form of suction mat or belt.

Figure 14 is a fragmentary plan view of the assembly shown in Figure 13. 7

Figure 15 is a sectional view of the apparatus illustrated in Figure 13 taken on a plane substantially indicated by the line I5-I5, and

Figure 16 is a plan view 'ofyet another form of suction mat or belt'capable of use. in apparatus of the character to which this invention pertains.

Referring now more specifically to the, drawings and more especially to Figure 1 the apparatus herein disclosed consists generally of a frame work indicated at I which may be conveniently fabricated from conventional structural steel shapes.- Rotatably supported in the frame I adjacent opposite ends thereof and driven by any suitable power means not shown are drums or pulleys 2 and 3. About the drums 2 and 3 there is trained an endless flexible suction belt or mat 3 of the character hereinafter more fully described. The frame! also carries a plurality of idler rolls such as 4 which cooperate to support the filter web generally indicated at 5 and which in its upper run overlies the upper run of the suction belt or mat 3, moves at a uniform rate of speed therewith and supports thereon the material being treated.

Rotatably supported on the upper portion of the frame I are spaced pulleys 6 about which are trained conventional deckle straps 1 which in their lower run rest upon the filter web 5 and laterally define the filter cake built upon the upper surface of such filter web.

Mounted on the frame I adjacent the feeding or receiving end of the machine is a transversely extending trough 8. The material to be treated may be fed to the trough 8 by any suitable means such as a conduit 9. An apron I extends from the trough 8 downwardly to the filter web to convey thereonto the material to be treated from the feed trough 8.

Mounted above the feeding or receiving end of the machine is an auxiliary feeding device generally indicated at II and comprising a Venturi shaped hopper l2 into the throat of which there extends an airpipe I3. The material to be fed by such auxiliary feeding means II is introduced to the hopper I2 either by means of the screw conveyor I4 and/or the conduit I5. At this point it should be noted that the lower or discharge end of the hopper I2 is flared transversely of the machine so that the material passing downwardly therethrough is deposited sub stantially uniformly transversely of either the material flowing downwardly over the apron I0 or such material after the same has been deposited on the filter web5.

A modified form of supplemental feeding means is illustrated at I6 in Figure 2; and comprises a hopper I'I having its lower open end positioned above either the apron III or the upper active surface of the filter web 5. Within the hopper I! there may be rotatably mounted an agitator or impeller generally indicated at I8 which may be provided with any suitable driving means such as a pulley I9 about which a driven belt may be trained. Here again the lower end of the hopper II will be so formed that it will deposit a substantially uniform layer of material transversely of either the apron III or the web 5.

Positioned either on opposite sides of the machine or in,av single or plurality of rows intermediate the opposite sides of the machine are a plurality of suction'boxes generally indicated at 29, 2|, 22, 23, 24 and 25. en a suction web or mat such as is illustratedt'in Figures 5 to 7 is' employed the suction boxes 20 to 2'5 willbe positioned along opposite sides of the machine. If

suction belts or mats such as are disclosed inv Figures 8 to 15 are employed the suction boxes will be arranged either in a single or a plurality of rows longitudinally of the machine and intermediately of the side edges of the suction belt or mat. When a suction belt or mat similar to that illustrated in Figure 16 is employed the suction boxes 20 to 25 may extend transversely of the entire widthof the suction belt and for certain purposes it may be possible to employ a single suction box covering the entire lower surface of the upper run of a suction belt of the character disclosed in Figure 16. The employment of a plurality of suction boxes will, however, provide a sufficiently flexible construction so that the mode of operation of the apparatus may be varied in a manner-not possible when Only one suction box is employed.

Adjacent the discharge or right hand end of the machine as viewed. in Figure 1 there is mounted a discharge roller about which the filter web 5 is trained and the construction of which is most clearly illustrated in Figures 3 and .4.-

The discharge roller 26 is rotatably supported between fixed spaced brackets 21 and 28 on opposite sides of the machine. A cut-off wire 29 is stretched between the standards 21 and 28 and the wire is so positioned as to be in engagement with the filter web 5 passing under such wire and over roll 26. One end 30 of the wire 29 passes through an opening provided therefor in the securing the end of the wire 29 at any selected This mode ofsupporting the cut-01f wire 29 causes such wire position within the groove 33.

to pass in a substantially helical manner from one end of the roll 26 to the other and :by the provision of the adjusting means above described the extent of angular displacements of the two ends of the wire on the roll 26 may be conveniently varied to suit particular operating conditions and types of material.

While a wire. 29 has been shown as the means for cutting oif the filter cake from the filter web, it shouldbe noted that it is within the contemplation of my invention to employ any other suitable means for such purpose such as a flat metallic band having-a sharp edge, which band may be pressed againstthe roll 25 either helically in the manner above defined, or truly axially of the roller, depending upon the particular operating conditions of the apparatus and the types of material being operated upon.

The suction belt or mat illustrated in Figures 5, 6 and '7 is characterized by the provision of a plurality of suction ports generally indicated at 35 on the inner face of the belt. The main body of the belt and more particularly the arrange- 'ment therein of the suction passages, openings,

etc. of the belt as illustrated in Figures 5 to 7 may be any arrangement such as is illustrated in the above identified co-pending application of William R. Thomson, as well as the expedients disclosed in this application in Figures 8 to 16.

The particular feature of novelty possessed by the belt illustrated in Figures 5 to 7 is the provision of a plurality of metallic inserts generally indicated at 36 between the suction ports and preferably extending to the edges of such ports. These metallic inserts provide means wherewith sprocket teeth on either or both of the drums 2 and 3 may engage in order to insure positive driving communications between such drumor drums andthe belt. The metallic inserts 36 are preferably slightly spaced as at 31 so as to provide areas therebetween in which the belt may freely flex as it passes around the drums 2 and 3. It will be evident; of course, that while inserts of substantially I-shape are admirably suited for use in conjunction with substantially rectangular suction ports such as 35, nevertheless, the contour of such inserts may be varied from the form illustrated either to accommodate particularly formed sprocket teeth on the drums 2 and 3 or to conform to difierently shaped suction ports.

In place of the metallic inserts molded in the mat between these suction ports I may utilize a aromas conventional type of sprocket chain which is molded in the mat for the same purpose and when the suction ports in the mat are arranged intermediately of its edges the opening between the links of such sprocket chain in the mat need not necessarily be suction ports but merely of such depth as to accommodate the sprocket teeth t carried by the drums about which the belt or mat is trained.

The suction belt or mat illustrated in Figures 8 to 10 will preferably be endless in form so as to be trained about drums such as 2 and 3 similarly to the manner in which the belt 3 is shown trained about such drums in Figure 1. The belt or mat generally indicated at 38 in Figure 8 is characterized by the provision on its outer or active face of substantially longitudinally extending drainage passages or grooves 39 which grooves are bridged at spaced points by partitions such as All. While the bridges fill have been shown as arranged in substantial alignment transversely of the belt or mat it may be desirable to stagger such bridges transversely of the belt.

The upper surface of the belt 38 is along opposite edges' provided with substantially smooth areas 4| on which the deckle straps will be supported. Intermediately of these flat marginal areas the belt will be provided with a plurality of relatively shallow closely spaced serrations providing ridges 42 therebetween so as to support the web such as 5 in a substantially continuous plane at a slight distance above the solid body of the belt. These ridges 42 may either be straight as shown or if preferred they may be of curved or zigzag contour. The only requirement being that the space between adjacent ridges drain into at least one of the drainage grooves 39. The vertical extent from the solid body of the belt of the ridges 42 and the distance between adjacent ridges will depend upon the character of the web 5 to be supported thereby. If a relatively thin web such as a fine silk is employed the ridges 42 should be relatively shallow and rather closely spaced in the nature of about to inch. If a heavier material such as canvas is employed as the filter web 5 the spacing between the ridges 42 and the depth of the grooves between such ridges may be appreciably greater than when a web of silk for example is employed.

The inner face of the belt 38 is provided with a plurality of spaced suction ports 43 which communicate with the drainage grooves 39 through passages 44. In Figures 8 and 9 the suction ports 43 have been shown as arranged adjacent the lateral edges of the belt 38.. It is within the contemplation of my invention, however, to arrange such ports either as a single row or a plurality of rows intermediately of the edges of the belt in which event the outer ends if no suction ports are provided at the edges of the belt will be closed and drainage effected through the centrally located ports. When the belt 38 is relatively narrow only one row of centrally located suction ports may be necessary and in case the belt 38 is of appreciable width two or more symmetrically arranged rows of suction ports may be provided intermediately of the edges of the belt and used either with or without rows of suction ports arranged at the extremities of the passages 44 i. e. adjacent the edges of the belt. The particular arrangement of the rows of suction ports in any of the above defined manners will of course determine the type of suction boxes to be employed in conjunction therewith.

With the suction ports arranged as illustrated in Figure 8, i. e., along opposite edges of the belt, two series of suction boxes such as 2am 25 positioned along opposite sides of the machine will be employed. If only a single row of suction ports 43 is provided such as may be arranged at the middle of the belt only one series of suction boxes such as 20 to 25 arranged centrally of the machine will be required.

The suction belt or mat illustrated in Figures 11 and 12 is generally similarto that shown in Figures 8 to 10 i. e. the suction belt or web extends continuously across the machine beneath the filter web 5 and is provided with a plurality of drainage grooves 45 in its upper face. The drainage grooves are provided with bridges 515 at spaced points and such bridges are preferably staggered transversely of the belt. The drainage grooves 55 in the belt 31! shown in Figure 11 are illustrated for purposes of convenience as extending substantially longitudinally of the belt, however, if desired such drainage grooves may be arranged transversely of the belt without departing from the principles of my invention.

The space in each drainage groove intermediately of the bridge walls 65 are providedwith openings 68 extending downwardly through the body of the belt and terminating in spaced suction ports on the inner periphery of the belt. The marginal areas 39 on the outer surface of the belt will be left flat similarly to the marginal portions M of the belt illustrated in Figure 9 for the purpose of providing a supporting surface for the deckle straps. The area between the marginal portions 69 of the belt t? will be serrated in any of the manners and for the purposes defined in connection with the serrations of the upper surface of the belt illustrated in Figure 8.

The supporting means for the filter web 5 illustrated in Figures 13 to 15 is different from the belts hereinbefore described in that in Figures 13 to 15 a plurality of separate laterally spaced belts 5D, 5i, 52 and 53 are employed instead of the single belts such as 38 and 41 respectively illustrated in Figures 8 and 10. When belts such as 50 to 53 are-employed in combination a slightly different form of supporting means therefor is likewise-necessary. In Figures 13 and 15 the supporting means for the belts 50 to 53 has been illustrated as comprising a plurality of suction boxes such as 54 and 55. Each of which may extend transversely of the ent re machine and be in abutting relation to a longitudinally contiguous similar suction box. The construction illustrated in Figures 13 and 15 has been shown for purposes of convenience only, it being within the contemplation of my invention to separate the suction boxes in the opposite direction.

The suction boxes illustrated in Figures 13 and 15 are provided with a supporting surface generally indicated at 56 which is provided with grooves 51 and ridges 58. The grooves 51 are for the purpose of providing lubrication and a seal for the lower face of the belts. The grooves 51 will preferably extend in a crisscross fashion on the upper face 56 of the suction boxes and one or more of such grooves may open at the inner edge of the belt supported thereover so that water flowing downwardly over the edge of such belt may flow into the groove and thus maintain the same filled.

The suction boxes are provided with spaced manifold connections 59 to which an outfall manifold 60 may be conveniently connected. The

passages extending upwardly through the suction boxes at 59 terminate on the upper face of such boxes between convergent ridges 58. These ridges 58 tend to maintain the belts in spaced relation and furthermore carry the water downwardly to the discharge ports. The edges 6| of the suctionboxes are flared upwardly so as to provide seepage collection troughs along opposite sides of the machine. Each of such seepage collection troughs may be provided with a conveniently located drainage opening not shown.

The upper face 56 of the'suction boxes is provided with longitudinally extending depressions of substantially the same width as the belts 50 to 53 for the purpose of insuring proper alignment of such belts on the machine.

In Fig. 13, as above indicated, the upper surfaces 56 of the suction boxes are provided with a plurality of ridgespositioned intermediately of the belts 50 to 53 for the purpose of maintaining such belts in proper alignment. It should be noted, however, at this point that it is within the contemplation of this invention to provide a smooth upper surface on the suction boxes or the means supporting the belts and to provide means associated with the respective belts such as laterally extending projections which maintain the belts in proper spaced relation and alignment. It is also within the contemplation of my invention to provide narrow spacing belts between the main belts of a width equivalent to the width of the ridges 58, but which belts instead of being as high as the belts 50 to 53 will be of the general form of the ridges 58, i. e., to a continuous base there will be applied projections and sloping faces similar to the projections 58 lying between adjacent belts.

The lateral outer belts 58 and 53 i. e. those along opposite sides of the machine are at their outer edges preferably provided with fiat areas 62 upon which the deckle straps 63 rest. The remaining upper surface of the belts 50 and 53 as well as the entire upper surface of belts 5| and 52 will be serrated in the manner and for the purposes in which the upper surfaces of previously described belts 38 and 4'! have been serrated.

The belts 50 to 53 shown in Figure 13, it will be noted, need not be provided with ports therethrough of any kind. The water which passes downwardly through the web 5 merely flows to the edges of the belts where it spills over into the space between such belts where it is drawn off through the passages at 59 and the manifold 60. When such construction is employed it will be evident that the belts 50 to 53 need not be truly continuous endless belts, inasmuch as the belts are not interposed in the vacuum; circuit they may be formed by lacing or similar securing together the ends of a flat band.

It will be noted that ridges 5ia are provided on certain of the belts such as 5| and 52 for the purpose of laterally dividing the area of the filter web into sections which are respectively served by the different drainage ports 59. The ridges 5ia not only have a tendency to direct the downwardly flowing water into the discharge openings in the suction boxes, but also may be conveniently utilized to separate the table into longitudinally extending laterally adjacent areas which, when separate outfall conduits are respectively attached to the suction ports 59, may be operated at a different degree of suction or air pressure.

When a construction such as is illustrated in Figures 13 to 15 is employed some means must be provided to seal the supporting table longitudinally between the belts at the ends of the machine. This may be conveniently accomplished as shown in the suction box 55 in Figure 15 by carrying the last ridge 58 between the belts upwardly into sliding engagement with the mat 5 as at 64. It is within the contemplation of my invention to provide a spring supported insert on the face 64 to resiliently engage the under surface of the mat 5 to further insure that a perfect seal will be secured in such area.

The belt shown in Figure 16 is different from any previously described form of construction in that such belt generally indicated at 65 extends laterally throughout the entire width of the filter web 5 and is provided with a plurality of particularly arranged openings generally indicated at 66 which pass directly downwardly through the belt 65. The marginal edges 61 of the belt 65 are formed similar to the marginal edges M of the belt 38 forthe support of the deckle straps. In addition the marginal edges 61 may be provided with spaced openings generally indicated at 68 for the reception of sprocket teeth formed on the drums such as 2 and 3 about whichthe belt will be trained. If desired metallic inserts such as 36 shown in Figures 5 and 6 may be employed around the openings 68 to reinforce the belt in the areas in which the same is engaged by the sprocket teeth.

The suction boxes which will be employed in connection with a belt such as 65 shown in Figure 16, will as previously indicated cover substantially the entire lower area of the upper run of such belt. The suction boxes upon which the belt 65 operates may be either a single suction box covering the entire upper run of the belt or such area may be sub-divided and thus covered by a plurality of adjacent suction boxes related to each other and to the belt area in any desired manner.

The surfaces of the suction box or boxes over which the belt 65 moves will be provided with a plurality of spaced suction ports generally indicated at 69 which are so spaced relatively to each other and to the ports or openings 66 in the belt that as the belt moves over the suction boxes at no time will all of the holes respectively formed in the suction boxes and the belt be in complete register. In the filtration of certain materials the actions set up by the intermittency of application of vacuum pressure on the material to be filtered gives a most desirable effect and a better extraction is obtained by such intermittent application and release of pressure. Furthermore, by the arrangement of the openings as illustrated in Figure 16 substantially the entire area of the belt may at one time or another be subjected to the action of the vacuum, but due to the fact that only'a portion of the belt is at any one time being operated upon a minimum amount of suction is.required.

The operation of the previously described apparatus is briefly as follows:

The material from which a portion of the liquid component is to be removed is fed to the machine by being passed downwardly over the apron Ill. The material is thus flowed onto the left hand portion of the upper run of the filter web 5. I have discovered that certain materials can best be thus dehydrated if the material, after being thus deposited on the filter web 5, is permitted a predetermined time interval within which to naturally stratify, i. e., within which the water content may be permitted. to fiow therefrom under the influence of gravity alone or only a very rial to be dehydrated will not be under the in-' slight amount of additional suction. To this end the filter box 20 is provided with a branched manifold 20a, each branch'being provided with valves, and such branches respectively leading to a free discharge and a suction conduit. By 0105- ing the valve from the suction conduit and opening the valve to the gravity discharge the matematerial were at once subject to suction and the finer constituents thereof were sucked into sealing engagement with the pores on the" surface of the filter web Certain' materials, if sufliciently coarse, so that this difilculty is not encountered, may of course, be subjected to an immediate suction in passing over the suction box 20 in which the valve to the gravity discharge would be'closed and the valve to the suction discharge open.

It should also be noted that permitting the material such as the sludge or slurry to drain by 3 gravity in the first stage or stages of the machine has the following and more particular advantage so far as the efficiency of operation of the machine as a whole is concerned.- As the clean and previously prepared filter medium is brought into the receiving area of the machine, its physical structure includes a large number of minute pores or passages which extend therepassages therethrough and through'which the water must pass. If no suction is employed in the opening stages of the operation, these capillary passages are not squeezed shut and the rate of passage of the water through the belt will be considerably more rapid under the influence of gravity than if suction were applied. However, after the major portion of the water has passed through the belt and after the above defined pores or passagesbecome partially clogged or so water-logged that the fiow of liquid therethrough is no longer free, the applibation of suction for the purpose of facilitating such flow: will increase the rate at which the water will pass downwardly through the filtering medium.

Most materials are so constituted that as the filter cake progresses towards the discharge end of the machine; the-most eflicient extractionof liquid from the filter cake will be accomplished by progressively increasing the degree of suction to which the filtering medium is subjected as it approaches the discharge end of the machine. There may be certain materials, however, which due to their particular nature or due to physical changes which occur in the filter cake during the drying cycle may be dried best if the degree of suction is varied somewhat differently from the manner above defined.

After the material has progressed to a position adjacent the discharge end of the machine, or for that matter at any stage of its travel over the suction boxes after the material has achieved a proper condition, it may be advantageously subjected to flow of air or gases at an elevated tem-- perature. This may be conveniently accomplished by positioning a hood generally indicated at 2411 over aportion of the filter cake, which hood is provided with a conduit 25a through which the gases at an elevated temperature are supplied. When operating on materials such as sewage sludges and the like in which thefilte'r cake is incinerated after being discharged from the filter machine, it iswithin the contemplation of my invention to dispose such incinerator immediately adjacent the discharge end ofthe filter and'to utilize the-waste heat from the incinerator to-provide the air or gases at an elevated temperature for-the hood 24. Itwill-be understood,

of course, that'the treating medium to which the filter cake may be subjected under the hood 24a. is not'limited to heatedgases resulting from incineration of. the discharged filter cakes Itis within the contemplation of my invention to employ heated airfor the purpose defined, regardless of the manner in which the same is heated, and for certain types of material it may be found advantageous to employ chemical. gases which will react with the filter cake or certain' constituents thereof.-

The use of :heated air Jr the various fluids as above defined for the purpose of treating the material being operated upon is not limited to the supplying of such treating medium to the filter cake by means of the hood 24, but such heated being treated through one of the suction or blower boxes such as 24.

The auxiliary, feeding devices I I and I6 are principally provided for the purpose of supplying air or the like may be introduced to the material to the material. being treated a constituent normally in place therein and which imparts a desirable characteristic to the filter cake which would otherwise not be possessed thereby. For instance, when treating materials in which the filter 'cake is finally disposed of by incineration,

and if such filter cake does not burn readily, it is within the contemplation of my invention to add a. combustible material such as wood, coal, coke, etc., in partially, or finely, divided form to the filter material by means of the auxiliary feeding devices I l and I6.

The type of material which maybe added to the material being treated by means of the-feeding devices such as and I6 is not limited to the above defined, but'may be any suitable material which will produce a desired modification in the filter cake either from the standpoint of its phys- 'ical or chemical compositionor both. It willbe noted that when certain finely divided materials are being operated upon, it will be advantageous to employ an additional material of the character. above defined which will not only primarily impart to the filtercake a diiferent characteristic than that which would normally be possessed thereby, but which will have the additional function of acting as a filter aid, i. e., it is within the contemplation of my invention to introduce to the material being filtered a substanceof such nature that when co-mingled with the solid constituents of the material will render the resultant filter cake of such cellular nature that dehydrae tion thereof may be carried on more efiiciently.

When a finely divided additional material is employed for any of the above purposes it may become necessary to either forcibly propel the same into the, wet material flowing down the from floating on top of the filter cake and thus be unevenly distributed therethrough. By utilizing the auxiliary feeder l6 such fine material may be mixed with a suitable liquid medium introduced through the conduit a to form a slurry which will readily mix with the wet material flowing downwardly over the apron I and therefore be uniformly co-mingled therewith.

It has been found that when operating upon materials having a very high liquid content improved results may be achieved by inclining the operative surface, i. e., the upper run of the web 5 or a part thereof to the horizontal so that the wet material when flowed onto the web will not flow backwardly over the feeding end of the web: 5 but instead flow forwardly into the gravity area previously referred to, and/or one or more of the initial suction stages. This inclination, as pre- .viously indicated, may extend throughout the entire upper run of the belt or mat and may be effected by tilting the entire machine; by a difference in elevation of the axes of the drums 2 and 3 or by a change in the diameter of either or both of such drums, or the inclined portion may extend for only a part of the upper run of the filter web,depending upon the particular material being operated upon as well as the condition of service.

When operating upon a material in which there is an appreciable solid content it-maybe advantageous to incline the filtering run of the web 5 in the opposite direction, i.- e., toward the receiving rather than the discharge end of the machine. This may be accomplished in any of the previously defined modes and the extent of such inclination as well as the degree of inclina- I therefore particularly point out and distinctly claim as my invention:

1. In apparatus of the character described, the combination with an endless filter web of means for supporting such web and causing a flow of air therethrough and the material supported thereon, said means comprising a stationary support provided with suction ports and a movable mat overlying said support and carrying said web, said mat provided with drainage grooves extending longitudinally of the mat and communicating with said suction ports.

2. In apparatus of the character described, the combination with an endless filter web of means for supporting such web and causing a flow'oi air therethrougli and the material supported thereon, comprising a stationary support provided with suction ports and a movable mat overlying said support and carrying said web,

with suction ports and a movable matoverlying saidsupport and carrying said web, said mat direction of movement -of said belt, communicating with said suction ports'and bridge walls extending transversely of said drainage areasand into substantial engagement with said mat.

4. In apparatus of the character described; the combination of a table provided witha plurality of spaced suction ports, a suction chamber in communication with said ports, a plurality of endless belts disposed laterally adjacent each other, supported externally of said suction chamber and having their upper runs supported on said table between said suction ports, and a filter web overlying said belts and supported thereby on said table. I 5. In apparatus of the character described, the combination of a table provided with a plurality of spaced suction ports, a suction chamber in communication with said ports, a plurality of endless belts disposed laterally adjacent each other, supported externally of said suction chamher and having their upper runs supported on" said table between said suction ports, and a filter web overlying said belts and supported thereby on said table.

combination of an endless flexible suction mat provided with a plurality of spaced suction ports on its inner periphery, reinforcing inserts in-said belt around said openings, spaced drums about i which saidbelt is trained and said drums provided, with projections arranged to extend into,

said suction ports to provide positive driving communication between said mat and said drums. "7. In apparatus of the character described, the combination of spaced drums, an endless suction web trained about said drums, and means for separating the material being treated from said web as the latter'passes around one of said drums, said means comprising a single wire under tension extending helically across the entire face of said web as the latter passes around its supporting drum at the discharge end of the machine.

-- WILLIAMCASEY.

\ provided with drainage grooves extending in the 40. 6. In apparatus of the character described, the 

